1. Field of the Invention
This invention relates to knitted reinforcement structures used for pressed or molded articles such as hoses for fluid conveyance.
2. Description of Related Art
U.S. Pat. No. 7,572,745 to Branch et al discloses an improved yarn for a knit reinforcement in a flexible hose. The flexible hose according to the invention may comprise a tube, a knit fabric, and a cover wherein said knit fabric comprises a hybrid yarn comprising a first yarn of co-para-aramid fibers and a second yarn of meta-aramid fibers. The co-para-aramid and meta-aramid yarns may be twisted, plied, folded, or commingled together to form a single hybrid reinforcing yarn for the hose. The knit fabric may reside between a tube and a cover and/or may be embedded in a layer of the hose. One or more layers of a knit fabric of hybrid yarn may be the primary reinforcing member of a hose.
PCT publication number WO2010/131216 to Mezzalira et al describes a flexible hose comprising, as viewed from the inside, at least one first inner layer made of a first thermoplastic polymer material, at least one reinforcement layer composed of a plurality of yarns knitted together to form a plurality of stitches of tricot type, and at least one second layer made of a second thermoplastic polymer material. At least one first yarn of said yarns that form said at least one reinforcement layer is a high tenacity fiber and at least one second yarn is a polyester fiber yarn or the like interwoven with the first yarn. A method of making such hose is also described.
PCT publication number WO2012/000713 to Brettschneider et al describes an article composed of a polymeric material which has been provided with an embedded reinforcement which consists wholly or partly of a textile material, characterized in that, in a first reinforcement variant, the textile material consists exclusively of polyoxadiazole (POD) and/or a POD derivative and/or a POD copolymer, or, in a second reinforcement variant, the textile material is a textile material combination consisting of POD and/or a POD derivative and/or a POD copolymer, and of at least one further textile material which is not part of the aforementioned POD group, or, in a third reinforcement variant, the textile material comprises a material combination consisting of POD and/or a POD derivative and/or a POD copolymer and at least one further material which is not part of any textile group. The article is more particularly a hose, more particularly again a charge-air hose, consisting of an inner layer and an outer layer of a polymeric material and an embedded reinforcement, for example in the form of a POD knit.
There is an ongoing need to provide knitted fabrics of improved mechanical strength that can enhance the properties of articles comprising the fabric, for example to increase the pressure carrying capability of a rubber hose.